This fence line is the extreme end of the main Birkenau camp. We are facing
west. Scroll a bit past the guard tower to view the back end of the Memorial
with its flag poles for all the countries who's citizens lost their live here.
Scroll past the memorial and we are at the back end of Krematorium II.

This is where people just off the trains were brought and told they were about
to receive a disinfecting shower, and afterward... work. This is the last of
the world they would see. This is the last moment in the open air.

They were instructed to undress in the room below and put their clothes on
numbered wall pegs so they could find them afterward.

After awhile they would be herded into the gas chamber. The cutaway of a
pillar you see in the model photo is where the Zyclon B would be dropped in,
from the ceiling. On the outside SS with gas masks opened the cans of crystals
and poured them into these pillars.

As soon as the
people inside realized what was happening, they struggled to get away from the
gas seeping from them. There were peep holes for the SS to observe what was
happening inside. When all were dead the prisoner-workers (Sonderkommando) opened
the chamber, pulled out the bodies, shaved hair for use in German industry,
and pulled out gold fillings from teeth.

The photos
are close-ups of a clay model of Krematorium II, which is on exhibit
at the Auschwitz Museum. A panorama of the model can be seen here.